Modern integrated circuits are comprised of devices such as transistors formed in a semiconductor layer and electrically conductive wires formed in inter-level dielectric layers above the semiconductor layer that interconnect the devices into circuits. Because of its low resistance, copper has become a prime material for these wires. However, as the dimensions of the wires has decreased, defects such as voids have been found in narrow copper wires that locally increase the resistance of the copper wires and which can lead to circuit failures. Therefore there is a need for a fabrication process for copper interconnects that is less susceptible to voiding than current fabrication processes.